Spectracom VersaSync User Manual page 227

Oscillator Log
Displays log entries related to oscillator disciplining. Provides the calculated frequency error
periodically while synchronizing to a reference.
GPS Qualification Log
If VersaSync is connected to a GNSS antenna and is tracking satellites, this log contains a run-
ning hourly count of the number of GNSS satellites tracked each hour. This history data can be
used to determine if a GNSS reception problem exists and whether this is a continuous or inter-
mittent reception issue.
GNSS reception may be displayed as cyclic in nature. A cyclic 12 hour pattern of decreased
GNSS reception typically indicates that the GNSS antenna has an obstructed view of the hori-
zon. The GNSS satellites are in a 12-hour orbit, so if part of the sky is blocked by large obstruc-
tions, at the same time every day (at approximately 12 hour intervals), the GNSS reception
may be reduced or may vanish altogether. If this occurs, the antenna should be relocated to
afford it an unobstructed view of the sky.
Every hour (displayed in the log as UTC time), VersaSync counts the total number of satellites
that were tracked during that hour. The GNSS qualification log shows the number of satellites
that were tracked followed by the number of seconds that the particular number of satellites
were tracked during the hour (3600 seconds indicates a full hour). The number to the left of the
"=" sign indicates the number of satellites tracked and the number to the right of the "=" sign
indicates the number of seconds (out of a total of 3600 seconds in an hour) that the unit was
tracking that number of satellites. For example, "0=3600" indicates the unit was tracking 0 satel-
lites for the entire hour, while "0=2700 1=900" indicates the unit was tracking one satellite for
900 seconds, but for the remaining portion of the hour it was tracking zero satellites.
Every hourly entry in the log also contains a quality value, represented by "Q= xxxx" (where x
can be any number from 0000 through 3600). The Qualification log records how many satel-
lites were tracked over a given hour. If for every second of the hour a tracked satellite was in
view, the Quality value will equal 3600. For every second VersaSync tracked less than the min-
imum number of satellites, the value will be less than 3600. The minimum requirement is one
satellite at all times after the unit has completed the GNSS survey and indicates "Stationary". A
minimum of four satellites are required in order for the GNSS survey to be initially completed.
If all entries in the qualification log are displayed as "0=3600", a constant GNSS reception
problem exists, so the cause of the reception issue is continuous. If the unit occasionally shows
0=3600 but at other times shows that 1 through 12 have numbers of other than "0000", the
reception is intermittent, so the cause of the reception issue is intermittent. If the Quality value
normally equals 3600 but drops to lower than 3600 about every 12 hours, the issue is likely
caused by the GNSS antenna having an obstructed view of the sky.
CHAPTER •
4 VersaSync User Manual Rev. 6.0
Synchronized to PPS(0), stratum=0 : NTP is synchronized using the PPS reference clock
driver (which provides more stable NTP synchronization).
4.6 Quality Management
215